Modular energy absorbing capabilities achieved with compounded deformation mechanisms in composite AA6061-T6/PVC foam structures

Influence of Extruded Tubing and Foam-Filler Material Pairing on the Energy Absorption of Composite AA6061/PVC Structures

“…The AA6061 tubes were combined concentrically with internal PVC foam cores, the latter were obtained from 25.4 mm-thick rectangular sheets utilizing a hole saw to match the inner profile of the extruded tubing. The cylindrical foam cores were fabricated utilizing a hole saw mounted to a Bridgeport ® with the arbor removed from rectangular sheets, consistent with previous studies [ 56 , 57 , 64 ]. A 0.40 mm clearance fit was achieved between these entities, and no adhesives were applied at the tubing/foam contact interface.…”

“…An orthotropic crushable foam model (*MAT_HONEYCOMB_026 in LS-DYNA ® , Livermore Software Technology Corporation, Livermore, CA, USA)) was utilized to replicate the quasi-static compressive stress/strain responses of the H-series PVC foam cores with the data originally presented in Section 2.1.2 . The compressive stress/strain responses were fitted to the Avalle model to omit the post-yield stress drop-off, consistent with [ 57 ].…”

“…This in-plane foam expansion cannot be modeled utilizing current releases of commercially available finite element software packages, including LS-DYNA ® , since the standard numerical models available for structural foams demand a zero-value for the Poisson's ratio. A translational nonlinear spring was introduced between the foam cores subjected to 10-bladed cutting/clamping (originally shown in Figure 4b), with the volumetric strain due to in-plane deformation, ε IPD , related to the crosshead displacement, x [57]:…”

“…Readers are encouraged to seek out the mentioned references for thorough, stepby-step derivations and discussions of the underlying theory. The total reaction force associated with a compounded cutting/foam crushing deformation mode, F cfc , can be generically stated as [57]…”

“…Near-constant reaction forces were experimentally achieved for extruded metallic tubing subjected to axial splitting with simultaneously occurring uniform compression of solid [ 51 ] and sandwiched [ 52 , 53 ] aluminum-based Alulight ® (Alulight GmbH, Ranshofen, Austria) internal foam cores. Closed-cell polyvinyl chloride (PVC) foams have also shown promise for enhancing many lightweight structural applications, including various energy absorbers [ 54 , 55 , 56 ], and were correspondingly combined with AA6061 tubing subjected to axial cutting [ 57 ] and hybrid cutting/clamping [ 58 ] with high efficacy. However, the concept is relatively new, and thus findings in the current literature are limited.…”